U.S. President Donald Trump has approved a four-point policy plan on North Korea revolving around using "every possible pressure" while looking for a diplomatic solution, a South Korean lawmaker said Thursday.

A bipartisan group of South Korean politicians met with Joseph Yun, the U.S. special representative for North Korea policy, in Washington D.C.

Trump signed a comprehensive policy report by the State Department about two weeks ago, Yun was quoted as saying by Rep. Kim Kwan-young of the opposition People's Party.

It includes four main strategies -- not recognizing North Korea as a nuclear state, imposing every possible sanction and pressure, not seeking a regime change and resolving the problem with dialogue in the end.

It means the Trump administration may have ruled out a military option for the Kim Jong-un regime, which has ratcheted up military threats with a series of ballistic missile launches and nuclear testing.

In general, it appears to be in line with the Obama government's strategy.

A composite photo of U.S. President Donald Trump (L) and North Korean leader Kim Jong-un (Yonhap)

In the early weeks of the Trump administration, U.S. officials talked tough about North Korea.

On a trip to Seoul in March, Secretary of State Rex Tillerson stated that the era of so-called strategic patience with Pyongyang is over. He added "all options" were on the table.

Trump, speaking in an interview with the Financial Times later, suggested his willingness to take unilateral military action, saying, "If China is not going to solve North Korea, we will."

He then dispatched the USS Carl Vinson aircraft carrier to Korea in a show of force, triggering public worries about a possible pre-emptive strike.

But Trump suddenly shifted to a rather soft tone, briefing members of U.S. Congress about North Korea in late April.

The maverick president even said he would be "honored" to meet the North's leader under the "right circumstances."

South Korea is expected to figure out more details of Trump's North Korea policy, which has been confusing, when President Moon Jae-in holds summit talks with him in the U.S. capital late next month. (Yonhap)